package com.atjinggu.jinggumail.member.test;

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.http.HttpMethod;
import org.springframework.http.client.ClientHttpRequest;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.client.*;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.List;
import java.util.Random;

/**
 * |                  ,;,,;
 * |                ,;;'(    社
 * |      __      ,;;' ' \   会
 * |   /'  '\'~~'~' \ /'\.)  主
 * | ,;(      )    /  |.     义
 * |,;' \    /-.,,(   ) \    码
 * |     ) /       ) / )|    农
 * |     ||        ||  \)
 * |     (_\       (_\
 *
 * @author ：jingming
 * @date ：Created in 2021/8/2 19:22
 * @version: V1.0
 * @slogan: 天下风云出我辈，一入代码岁月催
 * @description:
 **/
    @Slf4j
    public class TulingRestTemplate extends RestTemplate {

        private DiscoveryClient discoveryClient;

        public TulingRestTemplate (DiscoveryClient discoveryClient) {
            this.discoveryClient = discoveryClient;
        }

        protected <T> T doExecute(URI url, @Nullable HttpMethod method, @Nullable RequestCallback requestCallback,
                                  @Nullable ResponseExtractor<T> responseExtractor) throws RestClientException {

            Assert.notNull(url, "URI is required");
            Assert.notNull(method, "HttpMethod is required");
            ClientHttpResponse response = null;
            try {
                //判断url的拦截路径,然后去redis(作为注册中心)获取地址随机选取一个
                log.info("请求的url路径为:{}",url);
                url = replaceUrl(url);
                log.info("替换后的路径:{}",url);
                ClientHttpRequest request = createRequest(url, method);
                if (requestCallback != null) {
                    requestCallback.doWithRequest(request);
                }
                response = request.execute();
                handleResponse(url, method, response);
                return (responseExtractor != null ? responseExtractor.extractData(response) : null);
            }
            catch (IOException ex) { String resource = url.toString();
                String query = url.getRawQuery();
                resource = (query != null ? resource.substring(0,
                        resource.indexOf('?')) : resource);
                throw new ResourceAccessException("I/O error on " + method.name() +
                        " request for \"" + resource + "\": " + ex.getMessage(), ex);
            } finally {
                if (response != null) {
                    response.close();
                }
            }
        }


        /**
         * 把服务实例名称替换为ip:端口
         * @param url
         * @return
         */
        private URI replaceUrl(URI url){
            //解析我们的微服务的名称
            String sourceUrl = url.toString();
            String [] httpUrl = sourceUrl.split("//");
            int index = httpUrl[1].replaceFirst("/","@").indexOf("@");
            String serviceName = httpUrl[1].substring(0,index);

            //通过微服务的名称去nacos服务端获取 对应的实例列表
            List<ServiceInstance> serviceInstanceList = discoveryClient.getInstances(serviceName);
            if(serviceInstanceList.isEmpty()) {
                throw new RuntimeException("没有可用的微服务实例列表:"+serviceName);
            }

            //采取随机的获取一个
            Random random = new Random();
            Integer randomIndex = random.nextInt(serviceInstanceList.size());
            log.info("随机下标:{}",randomIndex);
            String serviceIp = serviceInstanceList.get(randomIndex).getUri().toString();
            log.info("随机选举的服务IP:{}",serviceIp);
            String targetSource = httpUrl[1].replace(serviceName,serviceIp);
            try {
                return new URI(targetSource);
            } catch (URISyntaxException e) {
                e.printStackTrace();
            }
            return url;
        }

    }